The disclosure relates to casting of single-crystal components. More particularly, the disclosure relates to manufacture of single crystal plates.
There is no simple way to make large sheets of nickel base superalloy single crystal other than by directional solidification of an investment cast mold. This is limited by furnace size and both in terms of diameter of the furnace and height to which the mold can be withdrawn. With the application of single crystal technology to manufacture of industrial gas turbine blades the required furnace size has expanded and currently it may be approaching several feet in diameter and height of withdrawal. But use of this process may require much higher investment, including liquid metal cooling, or otherwise may face the technical challenge of maintaining the thermal gradient as the bottom chill plate is withdrawn beyond a certain height.